Problem: If $x \boxdot y = xy+2x-y$ and $x \triangleright y = x^{2}+4y^{2}$, find $(-2 \triangleright -4) \boxdot -2$.
Answer: First, find $-2 \triangleright -4$ $ -2 \triangleright -4 = (-2)^{2}+4(-4)^{2}$ $ \hphantom{-2 \triangleright -4} = 68$ Now, find $68 \boxdot -2$ $ 68 \boxdot -2 = (68)(-2)+(2)(68)-(-2)$ $ \hphantom{68 \boxdot -2} = 2$.